<meta charset="utf-8">
(#) Use FragmentContainerView instead of the <fragment> tag

!!! WARNING: Use FragmentContainerView instead of the <fragment> tag
   This is a warning.

Id
:   `FragmentTagUsage`
Summary
:   Use FragmentContainerView instead of the <fragment> tag
Severity
:   Warning
Category
:   Correctness
Platform
:   Android
Vendor
:   Android Open Source Project
Identifier
:   androidx.fragment
Feedback
:   https://issuetracker.google.com/issues/new?component=460964
Min
:   Lint 7.0
Compiled
:   Lint 8.0 and 8.1
Artifact
:   [androidx.fragment:fragment](androidx_fragment_fragment.md.html)
Since
:   1.2.0
Affects
:   Resource files
Editing
:   This check runs on the fly in the IDE editor
See
:   https://developer.android.com/reference/androidx/fragment/app/FragmentContainerView.html
Implementation
:   [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/fragment/fragment-lint/src/main/java/androidx/fragment/lint/FragmentTagDetector.kt)
Tests
:   [Source Code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/fragment/fragment-lint/src/test/java/androidx/fragment/lint/FragmentTagDetectorTest.kt)
Copyright Year
:   2019

FragmentContainerView replaces the <fragment> tag as the preferred
          way of adding fragments via XML. Unlike the <fragment> tag,
FragmentContainerView                 uses a normal
`FragmentTransaction` under the hood to add the initial fragment,
         allowing further FragmentTransaction operations on the
FragmentContainerView                 and providing a consistent timing
for lifecycle events.

(##) Example

Here is an example of lint warnings produced by this check:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text
res/layout/layout.xml:5:Warning: Replace the <fragment> tag with
FragmentContainerView. [FragmentTagUsage]
    &lt;fragment android:name="androidx.fragment.app.Test'$'InflatedFragment"
     --------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here is the source file referenced above:

`res/layout/layout.xml`:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~xml linenumbers
&lt;FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"&gt;
    &lt;fragment android:name="androidx.fragment.app.Test'$'InflatedFragment"
              android:id="@+id/child_fragment"
              android:layout_width="match_parent"
              android:layout_height="match_parent" /&gt;
&lt;/FrameLayout&gt;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can also visit the
[source code](https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:/fragment/fragment-lint/src/test/java/androidx/fragment/lint/FragmentTagDetectorTest.kt)
for the unit tests for this check to see additional scenarios.

The above example was automatically extracted from the first unit test
found for this lint check, `FragmentTagDetector.expectFail`.
To report a problem with this extracted sample, visit
https://issuetracker.google.com/issues/new?component=460964.

(##) Including

!!!
   This is not a built-in check. To include it, add the below dependency
   to your project.

```
// build.gradle.kts
implementation("androidx.fragment:fragment:1.8.5")

// build.gradle
implementation 'androidx.fragment:fragment:1.8.5'

// build.gradle.kts with version catalogs:
implementation(libs.fragment)

# libs.versions.toml
[versions]
fragment = "1.8.5"
[libraries]
# For clarity and text wrapping purposes the following declaration is
# shown split up across lines, but in TOML it needs to be on a single
# line (see https://github.com/toml-lang/toml/issues/516) so adjust
# when pasting into libs.versions.toml:
fragment = {
    module = "androidx.fragment:fragment",
    version.ref = "fragment"
}
```

1.8.5 is the version this documentation was generated from;
there may be newer versions available.

[Additional details about androidx.fragment:fragment](androidx_fragment_fragment.md.html).
(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Adding the suppression attribute `tools:ignore="FragmentTagUsage"`
  on the problematic XML element (or one of its enclosing elements).
  You may also need to add the following namespace declaration on the
  root element in the XML file if it's not already there:
  `xmlns:tools="http://schemas.android.com/tools"`.

  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;fragment xmlns:tools="http://schemas.android.com/tools"
      tools:ignore="FragmentTagUsage" ...&gt;
    ...
  &lt;/fragment&gt;
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="FragmentTagUsage" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'FragmentTagUsage'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore FragmentTagUsage ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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